Workshop on Electronic Texts · Library of Congress
SESSION II. SHOW AND TELL
CD-ROM software does not network for a variety of reasons, LYNCH said. He speculated that CD-ROM publishers are not eager to have their products really hook into wide area networks, because they fear it will make their data suppliers nervous. Moreover, until relatively recently, one had to be rather adroit to run a full TCP/IP stack plus applications on a PC-size machine, whereas nowadays it is becoming easier as PCs grow bigger and faster. LYNCH also speculated that software providers had not heard from their customers until the last year or so, or had not heard from enough of their customers. ****** +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ BESSER * Implications of disseminating images on the network; planning the distribution of multimedia documents poses two critical implementation problems * Layered approach represents the way to deal with users' capabilities * Problems in platform design; file size and its implications for networking * Transmission of megabyte size images impractical * Compression and decompression at the user's end * Promising trends for compression * A disadvantage of using X-Windows * A project at the Smithsonian that mounts images on several networks * +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Howard BESSER, School of Library and Information Science, University of Pittsburgh, spoke primarily about multimedia, focusing on images and the broad implications of disseminating them on the network. He argued that planning the distribution of multimedia documents posed two critical implementation problems, which he framed in the form of two questions: 1) What platform will one use and what hardware and software will users have for viewing of the material? and 2) How can one deliver a sufficiently robust set of information in an accessible format in a reasonable amount of time? Depending on whether network or CD-ROM is the medium used, this question raises different issues of storage, compression, and transmission.
Concerning the design of platforms (e.g., sound, gray scale, simple color, etc.) and the various capabilities users may have, BESSER maintained that a layered approach was the way to deal with users' capabilities. A result would be that users with less powerful workstations would simply have less functionality. He urged members of the audience to advocate standards and accompanying software that handle layered functionality across a wide variety of platforms. BESSER also addressed problems in platform design, namely, deciding how large a machine to design for situations when the largest number of users have the lowest level of the machine, and one desires higher functionality. BESSER then proceeded to the question of file size and its implications for networking. He discussed still images in the main. For example, a digital color image that fills the screen of a standard mega-pel workstation (Sun or Next) will require one megabyte of storage for an eight-bit image or three megabytes of storage for a true color or twenty-four-bit image. Lossless compression algorithms (that is, computational procedures in which no data is lost in the process of compressing [and decompressing] an image--the exact bit-representation is maintained) might bring storage down to a third of a megabyte per image, but not much further than that. The question of size makes it difficult to fit an appropriately sized set of these images on a single disk or to transmit them quickly enough on a network.
With these full screen mega-pel images that constitute a third of a megabyte, one gets 1,000-3,000 full-screen images on a one-gigabyte disk; a standard CD-ROM represents approximately 60 percent of that. Storing images the size of a PC screen (just 8 bit color) increases storage capacity to 4,000-12,000 images per gigabyte; 60 percent of that gives one the size of a CD-ROM, which in turn creates a major problem. One cannot have full-screen, full-color images with lossless compression; one must compress them or use a lower resolution. For megabyte-size images, anything slower than a T-1 speed is impractical. For example, on a fifty-six-kilobaud line, it takes three minutes to transfer a one-megabyte file, if it is not compressed; and this speed assumes ideal circumstances (no other user contending for network bandwidth). Thus, questions of disk access, remote display, and current telephone connection speed make transmission of megabyte-size images impractical. BESSER then discussed ways to deal with these large images, for example, compression and decompression at the user's end. In this connection, the issues of how much one is willing to lose in the compression process and what image quality one needs in the first place are unknown. But what is known is that compression entails some loss of data. BESSER urged that more studies be conducted on image quality in different situations, for example, what kind of images are needed for what kind of disciplines, and what kind of image quality is needed for a browsing tool, an intermediate viewing tool, and archiving.
BESSER remarked two promising trends for compression: from a technical perspective, algorithms that use what is called subjective redundancy employ principles from visual psycho-physics to identify and remove information from the image that the human eye cannot perceive; from an interchange and interoperability perspective, the JPEG (i.e., Joint Photographic Experts Group, an ISO standard) compression algorithms also offer promise. These issues of compression and decompression, BESSER argued, resembled those raised earlier concerning the design of different platforms. Gauging the capabilities of potential users constitutes a primary goal. BESSER advocated layering or separating the images from the applications that retrieve and display them, to avoid tying them to particular software. BESSER detailed several lessons learned from his work at Berkeley with Imagequery, especially the advantages and disadvantages of using X-Windows. In the latter category, for example, retrieval is tied directly to one's data, an intolerable situation in the long run on a networked system. Finally, BESSER described a project of Jim Wallace at the Smithsonian Institution, who is mounting images in a extremely rudimentary way on the Compuserv and Genie networks and is preparing to mount them on America On Line. Although the average user takes over thirty minutes to download these images (assuming a fairly fast modem), nevertheless, images have been downloaded 25,000 times. BESSER concluded his talk with several comments on the business arrangement between the Smithsonian and Compuserv. He contended that not enough is known concerning the value of images.
LARSEN then illustrated the geometric growth over a two-year period-- through September 1991--of the number of networks that comprise the Internet. This growth has been sustained largely by the availability of three basic functions: electronic mail, file transfer (ftp), and remote log-on (telnet). LARSEN also reviewed the growth in the kind of traffic that occurs on the network. Network traffic reflects the joint contributions of a larger population of users and increasing use per user. Today one sees serious applications involving moving images across the network--a rarity ten years ago. LARSEN recalled and concurred with BESSER's main point that the interesting problems occur at the application level. LARSEN then illustrated a model of a library's roles and functions in a network environment. He noted, in particular, the placement of on-line catalogues onto the network and patrons obtaining access to the library increasingly through local networks, campus networks, and the Internet. LARSEN supported LYNCH's earlier suggestion that we need to address fundamental questions of networked information in order to build environments that scale in the information sense as well as in the physical sense.
LARSEN supported the role of the library system as the access point into the nation's electronic collections. Implementation of the Z39.50 protocol for information retrieval would make such access practical and feasible. For example, this would enable patrons in Maryland to search California libraries, or other libraries around the world that are conformant with Z39.50 in a manner that is familiar to University of Maryland patrons. This client-server model also supports moving beyond secondary content into primary content. (The notion of how one links from secondary content to primary content, LARSEN said, represents a fundamental problem that requires rigorous thought.) After noting numerous network experiments in accessing full-text materials, including projects supporting the ordering of materials across the network, LARSEN revisited the issue of transmitting high-density, high-resolution color images across the network and the large amounts of bandwidth they require. He went on to address the bandwidth and synchronization problems inherent in sending full-motion video across the network. LARSEN illustrated the trade-off between volumes of data in bytes or orders of magnitude and the potential usage of that data. He discussed transmission rates (particularly, the time it takes to move various forms of information), and what one could do with a network supporting multigigabit-per-second transmission. At the moment, the network environment includes a composite of data-transmission requirements, volumes and forms, going from steady to bursty (high-volume) and from very slow to very fast. This aggregate must be considered in the design, construction, and operation of multigigabyte networks.
Edwin BROWNRIGG, executive director, Memex Research Institute, first polled the audience in order to seek out regular users of the Internet as well as those planning to use it some time in the future. With nearly everybody in the room falling into one category or the other, BROWNRIGG made a point re access, namely that numerous individuals, especially those who use the Internet every day, take for granted their access to it, the speeds with which they are connected, and how well it all works. However, as BROWNRIGG discovered between 1987 and 1989 in Australia, if one wants access to the Internet but cannot afford it or has some physical boundary that prevents her or him from gaining access, it can be extremely frustrating. He suggested that because of economics and physical barriers we were beginning to create a world of haves and have-nots in the process of scholarly communication, even in the United States.
BROWNRIGG detailed the development of MELVYL in academic year 1980-81 in the Division of Library Automation at the University of California, in order to underscore the issue of access to the system, which at the outset was extremely limited. In short, the project needed to build a network, which at that time entailed use of satellite technology, that is, putting earth stations on campus and also acquiring some terrestrial links from the State of California's microwave system. The installation of satellite links, however, did not solve the problem (which actually formed part of a larger problem involving politics and financial resources). For while the project team could get a signal onto a campus, it had no means of distributing the signal throughout the campus. The solution involved adopting a recent development in wireless communication called packet radio, which combined the basic notion of packet-switching with radio. The project used this technology to get the signal from a point on campus where it came down, an earth station for example, into the libraries, because it found that wiring the libraries, especially the older marble buildings, would cost $2,000-$5,000 per terminal.
BROWNRIGG noted that, ten years ago, the project had neither the public policy nor the technology that would have allowed it to use packet radio in any meaningful way. Since then much had changed. He proceeded to detail research and development of the technology, how it is being deployed in California, and what direction he thought it would take. The design criteria are to produce a high-speed, one-time, low-cost, high-quality, secure, license-free device (packet radio) that one can plug in and play today, forget about it, and have access to the Internet. By high speed, BROWNRIGG meant 1 megabyte and 1.5 megabytes. Those units have been built, he continued, and are in the process of being type-certified by an independent underwriting laboratory so that they can be type-licensed by the Federal Communications Commission. As is the case with citizens band, one will be able to purchase a unit and not have to worry about applying for a license.
The basic idea, BROWNRIGG elaborated, is to take high-speed radio data transmission and create a backbone network that at certain strategic points in the network will "gateway" into a medium-speed packet radio (i.e., one that runs at 38.4 kilobytes), so that perhaps by 1994-1995 people, like those in the audience for the price of a VCR could purchase a medium-speed radio for the office or home, have full network connectivity to the Internet, and partake of all its services, with no need for an FCC license and no regular bill from the local common carrier. BROWNRIGG presented several details of a demonstration project currently taking place in San Diego and described plans, pending funding, to install a full-bore network in the San Francisco area. This network will have 600 nodes running at backbone speeds, and 100 of these nodes will be libraries, which in turn will be the gateway ports to the 38.4 kilobyte radios that will give coverage for the neighborhoods surrounding the libraries. BROWNRIGG next explained Part 15.247, a new rule within Title 47 of the Code of Federal Regulations enacted by the FCC in 1985. This rule challenged the industry, which has only now risen to the occasion, to build a radio that would run at no more than one watt of output power and use a fairly exotic method of modulating the radio wave called spread spectrum. Spread spectrum in fact permits the building of networks so that numerous data communications can occur simultaneously, without interfering with each other, within the same wide radio channel.
Anne KENNEY, associate director, Department of Preservation and Conservation, Cornell University, opened her talk by observing that the Cornell Xerox Project (CXP) has been guided by the assumption that the ability to produce printed facsimiles or to replace paper with paper would be important, at least for the present generation of users and equipment. She described three factors that influenced development of the project: 1) Because the project has emphasized the preservation of deteriorating brittle books, the quality of what was produced had to be sufficiently high to return a paper replacement to the shelf. CXP was only interested in using: 2) a system that was cost-effective, which meant that it had to be cost-competitive with the processes currently available, principally photocopy and microfilm, and 3) new or currently available product hardware and software.
KENNEY described the advantages that using digital technology offers over both photocopy and microfilm: 1) The potential exists to create a higher quality reproduction of a deteriorating original than conventional light-lens technology. 2) Because a digital image is an encoded representation, it can be reproduced again and again with no resulting loss of quality, as opposed to the situation with light-lens processes, in which there is discernible difference between a second and a subsequent generation of an image. 3) A digital image can be manipulated in a number of ways to improve image capture; for example, Xerox has developed a windowing application that enables one to capture a page containing both text and illustrations in a manner that optimizes the reproduction of both. (With light-lens technology, one must choose which to optimize, text or the illustration; in preservation microfilming, the current practice is to shoot an illustrated page twice, once to highlight the text and the second time to provide the best capture for the illustration.) 4) A digital image can also be edited, density levels adjusted to remove underlining and stains, and to increase legibility for faint documents. 5) On-screen inspection can take place at the time of initial setup and adjustments made prior to scanning, factors that substantially reduce the number of retakes required in quality control.
A primary goal of CXP has been to evaluate the paper output printed on the Xerox DocuTech, a high-speed printer that produces 600-dpi pages from scanned images at a rate of 135 pages a minute. KENNEY recounted several publishing challenges to represent faithful and legible reproductions of the originals that the 600-dpi copy for the most part successfully captured. For example, many of the deteriorating volumes in the project were heavily illustrated with fine line drawings or halftones or came in languages such as Japanese, in which the buildup of characters comprised of varying strokes is difficult to reproduce at lower resolutions; a surprising number of them came with annotations and mathematical formulas, which it was critical to be able to duplicate exactly. KENNEY noted that 1) the copies are being printed on paper that meets the ANSI standards for performance, 2) the DocuTech printer meets the machine and toner requirements for proper adhesion of print to page, as described by the National Archives, and thus 3) paper product is considered to be the archival equivalent of preservation photocopy. KENNEY then discussed several samples of the quality achieved in the project that had been distributed in a handout, for example, a copy of a print-on-demand version of the 1911 Reed lecture on the steam turbine, which contains halftones, line drawings, and illustrations embedded in text; the first four loose pages in the volume compared the capture capabilities of scanning to photocopy for a standard test target, the IEEE standard 167A 1987 test chart. In all instances scanning proved superior to photocopy, though only slightly more so in one.
Conceding the simplistic nature of her review of the quality of scanning to photocopy, KENNEY described it as one representation of the kinds of settings that could be used with scanning capabilities on the equipment CXP uses. KENNEY also pointed out that CXP investigated the quality achieved with binary scanning only, and noted the great promise in gray scale and color scanning, whose advantages and disadvantages need to be examined. She argued further that scanning resolutions and file formats can represent a complex trade-off between the time it takes to capture material, file size, fidelity to the original, and on-screen display; and printing and equipment availability. All these factors must be taken into consideration. CXP placed primary emphasis on the production in a timely and cost-effective manner of printed facsimiles that consisted largely of black-and-white text. With binary scanning, large files may be compressed efficiently and in a lossless manner (i.e., no data is lost in the process of compressing [and decompressing] an image--the exact bit-representation is maintained) using Group 4 CCITT (i.e., the French acronym for International Consultative Committee for Telegraph and Telephone) compression. CXP was getting compression ratios of about forty to one. Gray-scale compression, which primarily uses JPEG, is much less economical and can represent a lossy compression (i.e., not lossless), so that as one compresses and decompresses, the illustration is subtly changed. While binary files produce a high-quality printed version, it appears 1) that other combinations of spatial resolution with gray and/or color hold great promise as well, and 2) that gray scale can represent a tremendous advantage for on-screen viewing. The quality associated with binary and gray scale also depends on the equipment used. For instance, binary scanning produces a much better copy on a binary printer.
Among CXP's findings concerning the production of microfilm from digital files, KENNEY reported that the digital files for the same Reed lecture were used to produce sample film using an electron beam recorder. The resulting film was faithful to the image capture of the digital files, and while CXP felt that the text and image pages represented in the Reed lecture were superior to that of the light-lens film, the resolution readings for the 600 dpi were not as high as standard microfilming. KENNEY argued that the standards defined for light-lens technology are not totally transferable to a digital environment. Moreover, they are based on definition of quality for a preservation copy. Although making this case will prove to be a long, uphill struggle, CXP plans to continue to investigate the issue over the course of the next year. KENNEY concluded this portion of her talk with a discussion of the advantages of creating film: it can serve as a primary backup and as a preservation master to the digital file; it could then become the print or production master and service copies could be paper, film, optical disks, magnetic media, or on-screen display. Finally, KENNEY presented details re production: * Development and testing of a moderately-high resolution production scanning workstation represented a third goal of CXP; to date, 1,000 volumes have been scanned, or about 300,000 images.
Of course, with scanning, in addition to the paper facsimile, one is left with a digital file from which subsequent copies of the book can be produced for a fraction of the cost of photocopy, with readers afforded choices in the form of these copies. KENNEY concluded that digital technology offers an electronic means for a library preservation effort to pay for itself. If a brittle-book program included the means of disseminating reprints of books that are in demand by libraries and researchers alike, the initial investment in capture could be recovered and used to preserve additional but less popular books. She disclosed that an economic model for a self-sustaining program could be developed for CXP's report to the Commission on Preservation and Access (CPA). KENNEY stressed that the focus of CXP has been on obtaining high quality in a production environment. The use of digital technology is viewed as an affordable alternative to other reformatting options. ****** +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ANDRE * Overview and history of NATDP * Various agricultural CD-ROM products created inhouse and by service bureaus * Pilot project on Internet transmission * Additional products in progress * +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Pamela ANDRE, associate director for automation, National Agricultural Text Digitizing Program (NATDP), National Agricultural Library (NAL), presented an overview of NATDP, which has been underway at NAL the last four years, before Judith ZIDAR discussed the technical details. ANDRE defined agricultural information as a broad range of material going from basic and applied research in the hard sciences to the one-page pamphlets that are distributed by the cooperative state extension services on such things as how to grow blueberries.
NATDP began in late 1986 with a meeting of representatives from the land-grant library community to deal with the issue of electronic information. NAL and forty-five of these libraries banded together to establish this project--to evaluate the technology for converting what were then source documents in paper form into electronic form, to provide access to that digital information, and then to distribute it. Distributing that material to the community--the university community as well as the extension service community, potentially down to the county level--constituted the group's chief concern. Since January 1988 (when the microcomputer-based scanning system was installed at NAL), NATDP has done a variety of things, concerning which ZIDAR would provide further details. For example, the first technology considered in the project's discussion phase was digital videodisc, which indicates how long ago it was conceived. Over the four years of this project, four separate CD-ROM products on four different agricultural topics were created, two at a scanning-and-OCR station installed at NAL, and two by service bureaus. Thus, NATDP has gained comparative information in terms of those relative costs. Each of these products contained the full ASCII text as well as page images of the material, or between 4,000 and 6,000 pages of material on these disks. Topics included aquaculture, food, agriculture and science (i.e., international agriculture and research), acid rain, and Agent Orange, which was the final product distributed (approximately eighteen months before the Workshop).
The third phase of NATDP focused on delivery mechanisms other than CD-ROM. At the suggestion of Clifford LYNCH, who was a technical consultant to the project at this point, NATDP became involved with the Internet and initiated a project with the help of North Carolina State University, in which fourteen of the land-grant university libraries are transmitting digital images over the Internet in response to interlibrary loan requests--a topic for another meeting. At this point, the pilot project had been completed for about a year and the final report would be available shortly after the Workshop. In the meantime, the project's success had led to its extension. (ANDRE noted that one of the first things done under the program title was to select a retrieval package to use with subsequent products; Windows Personal Librarian was the package of choice after a lengthy evaluation.) Three additional products had been planned and were in progress: 1) An arrangement with the American Society of Agronomy--a professional society that has published the Agronomy Journal since about 1908--to scan and create bit-mapped images of its journal. ASA granted permission first to put and then to distribute this material in electronic form, to hold it at NAL, and to use these electronic images as a mechanism to deliver documents or print out material for patrons, among other uses. Effectively, NAL has the right to use this material in support of its program. (Significantly, this arrangement offers a potential cooperative model for working with other professional societies in agriculture to try to do the same thing--put the journals of particular interest to agriculture research into electronic form.)
Ideas discussed in this chapter
Text from Project Gutenberg, public domain in the United States.